This invention relates to a means which indicates the remaining capacity of a battery when it is under charge or discharge.
In general, the normal characteristic of a battery cannot be restored by charging after the ampere hour of discharge of the battery amounts to a certain value or more, and the life of the battery is shortened due to the deterioration of the electrodes of the battery. If an over-charge results while charging, it shortens the life of the battery as well. Thus, for the proper treatment of a battery, it is important to know its remaining capacity, to start the charging of the battery, and to stop it at a suitable time. In order to meet this requirement, those devices have been developed which can detect the ampere hour of discharge or of charge. The device to detect the ampere hour of discharge is fixed in a monitoring room for a large installation of electric power source, and is used effectively. The device to detect the ampere hour of charge is also fixed in the same room as a device separate from the previous one, and is used effectively as well.
An object of the present invention lies in detecting the remaining capacity of the battery, whether under charged or discharged, with a means of simple construction by measuring the voltage across the terminals of the battery without taking much time.
Another object of the present invention lies in providing a device for detecting the remaining capacity which can be manufactured as a compact and simply constructed unit, and can be set with ease especially in the restricted space in front of the driver's seat of a battery car and the like.